JP7481807B2 - Freeze Drying Equipment - Google Patents

Description

The present invention relates to a freeze-drying device for drying objects by freeze-drying.

The freeze-drying apparatus is equipped with a drying chamber having multiple shelves on which the objects to be dried are placed, a pressure reducing means for reducing the pressure inside the drying chamber, and a jacket that is provided on the wall of the drying chamber and circulates a heat transfer fluid. The flow rate of the heat transfer fluid is controlled so that the temperature of the jacket is approximately equal to the temperature of the objects placed on the shelves (see, for example, Patent Document 1).

Japanese Patent Publication No. 6-76868

As in Patent Document 1, controlling the flow rate of the heat transfer fluid so that the temperature of the jacket is equal to the temperature of the workpiece causes the following inconveniences. In other words, if the temperature of the entire workpiece is controlled to match the temperature of the lower temperature parts, the drying speed slows down and drying takes a long time. Also, if the jacket temperature is made too high in order to speed up the drying speed, the workpiece may reach or exceed its collapse temperature, causing collapse, in which the workpiece melts, leaving room for improvement.

Therefore, the present invention was made in consideration of such circumstances, and aims to provide a freeze-drying device that can prevent the occurrence of collapse while maintaining a high drying speed.

That is, in order to solve the above-mentioned problems, the freeze-drying apparatus of the present invention is characterized by comprising a container for accommodating the object to be treated, a pressure reducing means for reducing the pressure inside the container, a pressure detection means for detecting the pressure inside the container reduced by the pressure reducing means, and a heating means for heating the object to be treated, and a control unit for controlling the temperature of the heating means to increase or decrease based on the pressure inside the container detected by the pressure detection means.

As described above, the pressure inside the container can be detected by the pressure detection means, making it possible to grasp the reduced pressure state inside the container. The control unit then controls the temperature of the heating means to increase or decrease based on the pressure inside the container detected by the pressure detection means, thereby preventing the workpiece from collapsing due to a deterioration in the reduced pressure state while maintaining a fast drying speed.

The freeze-drying device of the present invention may also be configured such that the control unit controls the driving of the heating means so that the temperature of the heating means increases based on a threshold value related to a pressure drop when the pressure detected by the pressure detection means decreases.

As described above, the control unit controls the operation of the heating means so that the temperature of the heating means increases based on a threshold value related to the pressure drop when the pressure detected by the pressure detection means decreases, thereby enabling good freeze-drying.

The freeze-drying device of the present invention may also be configured such that the control unit controls the operation of the heating means so that the temperature of the heating means decreases based on a threshold value related to the increase in pressure when the pressure detected by the pressure detection means increases.

As described above, the control unit controls the operation of the heating means so that the temperature of the heating means decreases based on a threshold value related to the increase in pressure when the pressure detected by the pressure detection means increases, thereby preventing the reduced pressure state from worsening and causing the workpiece to collapse.

The freeze-drying device of the present invention may also be configured such that, if the control unit determines that there is an abnormality in the detection signal from the pressure detection means, it controls the driving of the heating means based on a predetermined time.

As configured above, if the control unit determines that there is an abnormality in the detection signal from the pressure detection means, it can control the operation of the heating means based on a predetermined time, thereby ensuring good freeze-drying of the object to be treated.

According to the present invention, it is possible to provide a freeze-drying device that can prevent the occurrence of collapse while maintaining a high drying speed by controlling the temperature of the heating means to increase or decrease based on the pressure inside the container.

1 is a side view of a reduced pressure drying apparatus according to the present invention. FIG. 4 is an enlarged view of a mounting portion of a filter provided in the reduced pressure drying apparatus. FIG. FIG. 2 is a side view showing the container of the reduced pressure drying apparatus rotated 180 degrees. 4 is a front view of a support frame that supports a filter portion of a filter provided in the reduced pressure drying apparatus. FIG. FIG. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5. 9 is a cross-sectional view taken along line IX-IX in FIG. 6. FIG. 2 is a front view of a filter portion of a filter provided in the reduced pressure drying apparatus. FIG. 11 is a longitudinal sectional view of a main part of the filter of FIG. 10 . 13(a) to 13(e) are schematic diagrams showing alternative forms of the filter. 1 is a graph showing the relationship between the pressure value inside the container and the jacket temperature with respect to the drying time. FIG. 2 is a control block diagram of the freeze-drying apparatus.

Below, one embodiment of the freeze-drying device according to the present invention will be described with reference to the drawings.

As shown in Figs. 1 and 2, the freeze-drying apparatus 1 includes a rotatably supported container 2 that contains the object to be treated, a vacuum pipe 3 for sucking the gas inside the container 2 to make the inside a reduced pressure state (also called a vacuum state), and a filter 4 for preventing the object to be treated supplied to the inside of the container 2 from being sucked into the vacuum pipe 3. The freeze-drying apparatus 1 of the present invention may be an agitator-type freeze-drying apparatus such as a vertical freeze-drying apparatus or a planetary motion freeze-drying apparatus, and the control of the present invention can be applied to the freeze-drying apparatus. The vertical freeze-drying apparatus is specifically a freeze-drying apparatus that combines an agitator with a vertical inverted cone-shaped container. The planetary motion freeze-drying apparatus is specifically a freeze-drying apparatus that performs freeze-drying by applying three-dimensional motion to the contents of an inverted cone-shaped sealed container by a screw blade that rotates and revolves around the container.

The freeze-drying device 1 rotates the container 2 to which the frozen material to be treated is supplied while maintaining a reduced pressure, thereby causing the solid (ice) contained in the material to change state (sublimate) to gas (water vapor), thereby drying the material to be treated. The container 2 is rotated intermittently or continuously depending on the state of the material to be treated, but in some cases it may be rotated so as to alternate between forward and reverse rotation.

The container 2 comprises a body wall 21 that defines an internal space, and a lid 22 that opens and closes the upper end of the body wall 21. The body wall 21 is configured in a roughly double cone shape (with a roughly octagonal outer shape) so that it can accommodate the material to be treated. A jacket 23 is disposed on the outside of the body wall 21 with a gap therebetween so as to cover the outside of the body wall 21.

The upper end of the main body wall 21 is provided with a cylindrical connection end 24 that closes the gap between the upper end of the main body wall 21 and the upper end of the jacket 23 and has an opening 24K for receiving the material to be treated. A circular step 24D with an L-shaped cross section is formed on the radially inner side of the upper end of the connection end 24 for mounting the flange portion 41F of the filter portion 41 described later.

The lower end surface 24A of the connection end 24 is tapered so that it widens outward as it goes downward, and the angle of the tapered surface is set to be the same as the tapered surface 21A on the inner surface of the main body wall 21 so that it is flush with the surface.

The lid 22 has a circular through hole 22A for connecting the vacuum pipe 3 therethrough, and constitutes a connection part for connecting the vacuum pipe 3. The inside of the container 2 is sealed by pressing this connection part (lid 22) against the connection end 24 from above to close the connection end 24. The lid 22 may be configured so that it can be opened and closed by manual operation force, or it may be configured so that it can be opened and closed by using the power of an actuator (not shown) such as an electric motor.

The container 2 also has an openable and closable discharge section 25 at the bottom end for discharging the dried material. The lid 22 and the discharge section 25 are arranged in opposing positions in the vertical direction. The container 2 also has a pressure detection means 17 (see FIG. 14) for detecting the pressure inside the container 2. This pressure detection means 17 is composed of a pressure sensor provided inside the container 2.

The heat medium heated by the heating means 18 (Fig. 14) is supplied from the heat medium supply hose 5 to the gap between the main body wall 21 and the jacket 23 to heat the container 2, which can further promote drying of the treated object. The supplied heat medium is recovered by the heat medium recovery hose 6, heated to a set temperature by the heating means, and then supplied to the container 2 through the heat medium supply hose 5. Hot water is used as the heat medium, but it may be a heated gas, or the container 2 may be directly heated by a heater, which is the heating means. In addition, a temperature detection means 19 (see Fig. 14) is provided to detect the temperature of the jacket 23. This temperature detection means 19 is composed of a temperature sensor provided in the jacket 23.

Hollow rotating shafts 7, 8 are attached to both opposing lateral sides of the jacket 23 of the vessel 2. These rotating shafts 7, 8 are rotatably supported by bearing devices 11, 12 attached to the upper ends of a pair of bearing pedestals 9, 10. A box 13 is attached to the base end side (vessel 2 side) of the rotating shaft 7 on the left side in FIG. 1. The lower ends of the pair of bearing pedestals 9, 10 are supported by a stand 14 placed on the floor or the like. The vessel 2 rotates together with the vacuum pipe 3 and the pair of rotating shafts 7, 8 around the horizontal axis X by a motor 15 attached to the bearing pedestal 10 on the right side in FIG. 1. FIG. 4 shows the vessel 2 rotated 180 degrees from the state in FIG. 1.

The vacuum piping 3 is configured in an arch shape and includes a first pipe 31 having a straight shape and one end (lower end) penetrating and attached to the lid 22, a second pipe 32 having a circular arc shape and one end (lower end) connected to the other end (upper end) of the first pipe 31, a flexible hose 33 having one end connected to the other end (left end) of the second pipe 32, a third pipe 34 having a substantially L-shape and one end connected to the other end (left end) of the flexible hose 33, and a fourth pipe 35 having a straight shape and connected to the other end (lower end) of the third pipe 34. The flexible hose 33 is provided to absorb the change in length of the vacuum piping 3 that occurs when the lid 22 is opened and closed.

The other end (lower end) of the fourth tube 35 is attached to the left rotating shaft 7 by penetrating it. The left end of the left rotating shaft 7 is connected in communication with one end of a straight tube 16 equipped with a reduced pressure vacuum pipe 16F. The fifth tube 16 is fixed to the left bearing base 9. Therefore, by operating a vacuum pump (not shown) connected to the reduced pressure vacuum pipe 16F via a hose, the gas in the container 2 is sucked through the reduced pressure vacuum pipe 16F, tube 16, and vacuum pipe 3 to reduce the pressure inside the container 2, thereby creating a reduced pressure inside the container 2. The reduced pressure pump, the tube 16 equipped with the reduced pressure vacuum pipe 16F, and the vacuum pipe 3 constitute a decompression means for reducing the pressure inside the container 2.

The filter 4 includes a filter portion 41 (see Figures 10 and 11) and a support frame 42 (see Figures 5 to 9) that supports the filter portion 41.

As shown in Figs. 10 and 11, the filter section 41 comprises a plurality of sewn mesh bodies 41A, 41B (two in this example), two ring-shaped, plate-shaped seal gaskets 41C, 41D as sealing materials for sealing the lid 22 when it is closed, and a ring-shaped, plate-shaped disk 41E made of synthetic resin (e.g., polypropylene) sandwiched between the seal gaskets 41C, 41D. The mesh bodies 41A, 41B are breathable over their entire area, which can further increase the intake efficiency. The mesh bodies 41A, 41B may be made of nonwoven fabric.

The mesh bodies 41A and 41B are provided with a first mesh body 41A that constitutes a vertical wall portion with an open lower end, and a second mesh body 41B that constitutes a horizontal wall portion as a cover portion that covers the open lower end. The outer peripheral edge of the second mesh body 41B is folded upward and sewn to the lower end of the first mesh body 41A to connect the two mesh bodies 41A and 41B. In addition, the upper edge of the first mesh body 41A is folded outward, and the folded outward part 41a is folded inward so as to wrap a pair of upper and lower seal gaskets 41C and 41D that sandwich a disk 41E in the vertical middle, and the folded tip is sewn to the horizontal side part of the first mesh body 41A to form a bottomed cylindrical (brimmed hat-shaped) filter part 41 having a flange part 41F with seal gaskets 41C and 41D at the upper end.

As shown in Figures 5 to 9, the support frame 42 is provided with a circular synthetic resin (or metal) perforated plate 42A with a number of openings 42a at the bottom, forming the bottom, an upper ring member 42B made of synthetic resin (or metal) in a ring shape at the top and forming a circular flange portion 42b, a plurality of (16) round bars 42C for vertically connecting the upper ring member 42B and the perforated plate 42A, an intermediate ring member 42D with an opening 42d at the center, which is attached to the approximate center of the round bars 42C in the vertical direction, a plurality of (8) vertically elongated reinforcing plates 42E attached from the inside of every other round bar 42C toward the center between the intermediate ring member 42D and the perforated plate 42A in the circumferential direction, and a ring-shaped synthetic resin (or metal) lining plate 42F attached to the outer periphery of the upper end of the round bars 42C and slightly protruding outward by its thickness.

The support frame 42 is configured as a bottomed cylinder (hat-shaped brim) with a diameter slightly smaller than that of the filter section 41. Therefore, the filter section 41 can be integrated by placing it over the support frame 42 from below (see FIG. 3). The flange section 41F of the filter section 41, located below the flange section 42b of the support frame 42 in which the support frame 42 and the filter section 41 are integrated in this way, is placed on the step section 24D of the connection end section 24. In this state, the lid 22 is pressed from above to seal the inside of the container 2.

As described above, the filter 4 has a first mesh body 41A that forms a vertical wall portion that protrudes from the connection portion (lid 22) toward the inside of the container 2, so the ventilation area of the gas can be increased by sucking through the second mesh body 41B that forms the horizontal wall portion and the first mesh body 41A that forms the vertical wall portion. This makes it possible to efficiently reduce the pressure inside the container and increase the drying efficiency.

Specifically, the extending end (lower end in the figure) of the vertical wall portion (first mesh body 41A) of the filter 4 extends further inside the container 2 than the lowermost end 24E of the connecting end 24 of the main body wall 21. In this way, if the extending end of the vertical wall portion (first mesh body 41A) of the filter 4 extends further inside the container 2 than the lowermost end 24E of the connecting end 24 of the main body wall 21, even if the filter 4 is covered by the object to be treated while the container 2 is being driven and rotated, the extending end side of the vertical wall portion (first mesh body 41A) of the filter 4 can be exposed early, so that the intake efficiency can be improved. In this embodiment, the extending end (lower end in the figure) of the vertical wall portion (first mesh body 41A) of the filter 4 extends further inside the container 2 than the lowermost end 24E of the connecting end 24 of the main body wall 21, but it may be located at any position within the processing space G where the object to be treated is dried. The processing space G is a space in which the object to be processed inside the container 2 is moved and dried by the rotation of the container 2, and includes a gap S between the inner surface of the connection end 24 of the main body wall 21 and the outer surface of the vertical wall portion (first mesh body 41A) of the filter 4. Therefore, the filter 4 may be configured so that the extension end (lower end in the figure) of the vertical wall portion (first mesh body 41A) of the filter 4 is located between the lower surface of the lid 22, which is the connection portion, below the step portion 24D of the connection end 24 and the upper lower end 24F of the connection end 24, or the extension end (lower end in the figure) of the vertical wall portion (first mesh body 41A) of the filter 4 is located between the upper lower end 24F of the connection end 24 and the lowest end 24E. The gap S may be filled with a member having sealing properties. In this case, the area below the upper lower end 24F of the connection end 24 becomes the processing space G. For example, if the top line of the workpiece D when it is supplied to the container 2 shown in FIG. 1 is set to the first line R1, when the container 2 shown in FIG. 4 is rotated 180 degrees, the top line of the workpiece becomes the second line R2. That is, in the second line R2 shown in FIG. 4, a part of the filter 4 (here, the extension end 4T and a part (extension end) of the vertical wall portion (first mesh body 41A)) is exposed. When the supply amount of the workpiece is set in this way, it is also possible to further extend the extension end 4T of the filter 4 in the extension direction (downward in FIG. 1). That is, in FIG. 1, the extension end 4T of the filter 4 can be extended in the extension direction (downward in FIG. 1) to any vertical position in the first processing space of the container 2 formed at the first vertical height L from the second line R2 of the workpiece to the horizontal axis X, and further downward from the horizontal axis X to any vertical position in the second processing space of the container 2 formed at the first vertical height L. In Fig. 1, the case where the filter 4 is extended up to the extension end 4T1 is shown by a dashed line, and even if extended in this manner, it will not come into contact with the first line R1 of the material to be treated supplied as shown in Fig. 1, and even if the container 2 shown in Fig. 4 is rotated 180 degrees, at least a part of the vertical wall portion (first mesh body 41A) will not be covered by the material to be treated. In this container 2, the lower processing space is set longer by the second vertical height l than the upper processing space across the horizontal axis X, so that the extension end 4T of the filter 4 can be extended from the horizontal axis X in Fig. 1 to a height obtained by adding the second vertical height l to the first vertical height L. FIG. 1 shows the case where the filter 4 is extended up to the extension end 4T2. Even when extended in this manner, it does not come into contact with the first line R1 of the material being treated as shown in FIG. 1, and even when the container 2 shown in FIG. 4 is rotated 180 degrees, at least a portion of the vertical wall portion (first mesh body 41A) is not covered by the material being treated.

For example, when 1% to 80% (preferably 1% to 65%, more preferably 1% to 45%) of the total capacity of the container 2 equipped with the filter 4 of the above configuration is stored in the container 2 and the container 2 is rotated to perform drying processing (particularly when the container 2 shown in FIG. 4 is rotated 180 degrees), it is preferable to form the vertical wall portion (first mesh body 41A) so that at least a part of the vertical wall portion is exposed from the object to be treated without being covered by the object. By forming the vertical wall portion in this manner, it is possible to increase the intake efficiency by sucking in from a part of the exposed vertical wall portion. When the capacity is set to 1% to 80% (when the capacity is large), the height of the filter 4 must be made higher than when the capacity is set to 1% to 65% or 1% to 45%, so while the intake efficiency can be increased, the higher height of the filter 4 is disadvantageous in terms of the cost and strength (durability) of the filter 4. In addition, when the amount of the treated material is 0.1% to 80% (preferably 0.1% to 65%, more preferably 0.1% to 45%, and even more preferably 0.1% to 10%) of the total capacity of the container 2 when the drying process of the treated material is completed while rotating the container 2 equipped with the filter 4 having the above configuration, it is preferable to form the vertical wall portion (first mesh body 41A) so that at least a part of the vertical wall portion is exposed from the treated material without being covered by the treated material. By forming the vertical wall portion in this manner, it is possible to increase the intake efficiency by sucking from a part of the exposed vertical wall portion. Similarly, in this case, when the amount of the treated material is 0.1% to 80% of the total capacity of the container when the drying process of the treated material is completed (when the amount of the treated material is large), the height of the filter 4 must be made higher than when the amount of the treated material is 0.1% to 65% or 0.1% to 45% of the total capacity of the container. Therefore, while the intake efficiency can be increased, the cost and strength (durability) of the filter 4 are disadvantageous because the height of the filter 4 is increased.

The freeze-drying device 1 also includes a control unit 20 that controls the operation of the heating means 18 so that the temperature of the heating means 18 increases or decreases based on the pressure inside the container 2 detected by the pressure detection means 17, as shown in FIG. 14.

The control unit 20 controls the driving of the heating means 18 so that the temperature of the heating means 18 increases based on a first threshold value for pressure drop when the pressure detected by the pressure detection means 17 decreases, and controls the driving of the heating means 18 so that the temperature of the heating means 18 decreases based on a second threshold value for pressure increase when the pressure detected by the pressure detection means 17 increases. As shown in the graph of FIG. 13, the first threshold value for pressure drop is a lower limit value 26 of the pressure in the container 2 at which a high drying speed can be maintained without causing collapse even if the pressure reduction is promoted and the temperature in the container 2 is increased. The second threshold value for pressure increase is an upper limit value 27 of the pressure in the container 2 at which the degree of pressure reduction becomes poor due to an excessive drying speed or a clogged filter, etc., and is expected to cause collapse.

The thin dashed line 28 in FIG. 13 indicates the pressure value in the container 2 during normal operation, when the pressure in the container 2 is gradually reduced. When the pressure value detected by the pressure detection means 17 is between the upper limit 27 and the lower limit 26, as shown by the solid line 29 in FIG. 13, the operation of the heating means 18 is controlled so that the jacket temperature is maintained at a set temperature (here, -10 degrees) slightly lower than the maximum temperature shown by the thick dashed line 30. Here, the set temperature is set to a temperature approximately halfway between the maximum temperature of the jacket temperature (the temperature shown by the thick dashed line 30) and the minimum temperature of the jacket temperature (the temperature shown by the dashed line 36), but it can also be set to any temperature lower than the maximum temperature of the jacket temperature. Also, when the pressure value detected by the pressure detection means 17 during drying operation becomes larger than the upper limit 27, the operation of the heating means 18 is controlled so as to lower the jacket temperature. Conversely, when the pressure value detected by the pressure detection means 17 becomes approximately equal to or smaller than the lower limit value 26, the control unit 20 determines that the decompression in the container 2 has been accelerated, and controls the operation of the heating means 18 to gradually increase the jacket temperature from the set temperature.

In addition, if the pressure value detected by the pressure detection means 17 exceeds the upper pressure limit value 27 even when the jacket temperature is lowered to the minimum jacket temperature (the temperature indicated by the dashed dotted line 36), the control unit 20 determines that there is an abnormality in the pressure reducing pump or a sealing abnormality due to gas leakage from the piping, lid, etc., and may notify the operator of the error using a notification means such as a buzzer or indicator lamp, and may temporarily halt operation of the freeze-drying device 1.

The control unit 20 controls the operation of the heating means 18 during the actual drying process, as explained below with reference to the graph in Figure 13.

When a start switch (not shown) is pressed to freeze-dry the material supplied into the container 2, the vacuum pump is driven and begins to suck in the gas from the container 2 to reduce the pressure. When the vacuum pump is driven for a predetermined time, the pressure in the container 2 (see thin dashed line 28) reaches the upper limit 27, and then the pressure in the container 2 is further reduced to a predetermined value. If the pressure in the container 2 does not reach the upper limit 27 even after the predetermined time has passed, the control unit 20 determines that some kind of trouble has occurred and notifies the operator of the error using a notification means such as a buzzer or indicator lamp, and may temporarily halt operation of the freeze-drying device 1.

When the pressure inside the container 2 described above decreases to a predetermined value, and a predetermined time has passed, when the pressure inside the container 2 becomes approximately the same as or lower than the lower limit value 26 (see point 37 in FIG. 13), the control unit 20 determines that the pressure has been reduced and controls the operation of the heating means 18 to gradually increase the jacket temperature from the set temperature to dry the workpiece. If the pressure inside the container 2 becomes smaller (drops) than the upper limit value 27 and then exceeds the upper limit value 27, the control unit 20 controls the operation of the heating means 18 to lower the jacket temperature.

The control unit 20 also controls the container 2 to rotate intermittently or at a low speed at the beginning of the drying process, and when the pressure is reduced and the jacket temperature is increased, controls the rotation of the jacket to gradually increase in speed. Then, at the end of the drying process, that is, after the jacket temperature has increased to the maximum temperature (20°C in FIG. 13), the rotation is made even faster. In this way, it is preferable to control the rotation speed of the container 2 in accordance with the jacket temperature. By controlling in this way, it is possible to accelerate the drying speed at the end of the drying process and shorten the drying time.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

In the above embodiment, the container 2 is provided with a lid 22 that can be opened and closed freely, but an opening for supplying the material to be treated from the outside into the container 2 can be provided on the periphery of the container 2. In this case, the opening constitutes the connection part.

In the above embodiment, the filter 4 is configured in a hat shape with a brim, but it may be configured as shown in Fig. 12(a) to (e). The figure shows the filter part 41, and does not show the support frame 42. In Fig. 12(a), the second net 41B, which is a cover part covering the extended end (lower end in the figure) of the first net 41A, which is a vertical wall part, is configured in a cone shape that protrudes downward toward the center. In Fig. 12(b), the second net 41B, which is a cover part covering the extended end of the first net 41A, which is a vertical wall part, is configured in an inverted cone shape that is concave upward toward the center. In Fig. 12(c), the first net 41A, which is a vertical wall part, is configured in a tapered shape that is located inward toward the bottom, and the second net 41B, which is a cover part covering the extended end of the first net 41A, is configured in a cone shape that protrudes downward toward the center. In FIG. 12(d), the first mesh body 41A, which is a vertical wall portion, is configured in an expanded shape that is positioned more outward as it goes downward, and the second mesh body 41B, which is a cover portion that covers the extended end of the first mesh body 41A, is configured in a horizontal plane shape. In FIG. 12(e), it is configured only with the first mesh body 41A, which is a vertical wall portion, without a cover portion. Specifically, the first mesh body 41A, which is a vertical wall portion, is configured in a bowl shape with six faces 41H. In this way, the shape or configuration of the filter portion 41 can be freely changed. The filter portion 41 may also have a pleated structure with multiple folds.

In addition, in the above embodiment, the filter 4 is shown to include the filter portion 41 and the support frame 42, but the filter 4 may be configured with only the filter portion 41, which has shape-retaining strength.

In the above embodiment, the first mesh body 41A, which is the vertical wall portion, is configured to be breathable over its entire area, but it may be configured to be breathable only in part. Also, the second mesh body 41B, which is the cover portion that covers the extended end of the first mesh body 41A, is configured to be breathable over its entire area, but it may be configured to be breathable only in part.

In the above embodiment, the threshold for pressure reduction is set to a lower limit, and the threshold for pressure increase is set to an upper limit. Alternatively, the threshold for pressure reduction may be set in advance as a rate at which the pressure in the container 2 drops, and the jacket temperature may be increased when the rate at which the pressure in the container 2 drops is equal to or greater than the set rate. Alternatively, the threshold for pressure increase may be set in advance as a rate at which the pressure in the container 2 rises, and the jacket temperature may be decreased when the rate at which the pressure in the container 2 rises is equal to or greater than the set rate.

1... freeze-drying apparatus, 2... container, 3... vacuum piping, 4... filter, 5... heat medium supply hose, 6... heat medium recovery hose, 7, 8... rotating shaft, 9, 10... bearing stand, 11, 12... bearing device, 13... box, 14... stand, 15... motor, 16... pipe, 16F... reduced pressure vacuum piping, 17... pressure detection means, 18... heating means, 19... temperature detection means, 20... control unit, 21... main body wall, 21A... tapered surface, 22... lid, 22A... through hole, 23... jacket, 24... connection end, 24A... lower end surface, 24D... step, 24E... lowest end, 24F... upper lower end, 24K... opening, 25... discharge section, 26... lower limit, 27... upper limit, 28... thin dashed line, 2 9...solid line, 30...thick dashed line, 31...first tube, 32...second tube, 33...flexible hose, 34...third tube, 35...fourth tube, 36...dash line, 37...point, 41...filter section, 41A...first mesh body (vertical wall section), 41B...second mesh body (horizontal wall section), 41C, 41D...seal gasket, 41E...disk, 41F...flange section, 41H...six faces, 41a...outwardly folded section, 42...support frame, 42A...perforated plate, 42B...upper ring member, 42C...round bar, 42D...intermediate ring member, 42E...reinforcing plate, 42F...stretching plate, 42a...opening, 42b...flange section, 42d...opening, G...treatment space, S...gap, X...horizontal axis

Claims (3)

The apparatus comprises a container for accommodating an object to be treated, a pressure reducing means for reducing the pressure inside the container, a pressure detecting means for detecting the pressure inside the container reduced by the pressure reducing means, and a heating means for heating the object to be treated,
a control unit configured to control the heating means in a driven state and to control the temperature of the heating means so as to increase or decrease based on the pressure in the container detected by the pressure detection means ;
The control unit controls the drive of the heating means so that, when the pressure inside the container detected by the pressure detection means decreases to a predetermined pressure as a result of the pressure reduction means reducing the pressure, the temperature of the heating means becomes a set temperature between a maximum temperature and a minimum temperature, and when the pressure falls below a lower limit pressure which is lower than the predetermined pressure while controlling the drive to reach the set temperature, controls the drive of the heating means so that the temperature of the heating means becomes higher than the set temperature . 2. The freeze-drying apparatus according to claim 1 , wherein the control unit controls driving of the heating means so that the temperature of the heating means decreases based on a threshold value related to a pressure increase when the pressure detected by the pressure detection means increases. 3. The freeze-drying apparatus according to claim 1, wherein the control unit controls the rotation of the container or the rotation of a blade provided in the container based on the pressure detected by the pressure detection means.